Consider the screen still until proven otherwise

In order to avoid always forcing static mode after initialization or
recentering, consider the screen still by default.

This required adding a defaultValue option to the detector, to be used
during the initialization period.

Test: atest --host libheadtracking-test
Change-Id: I7f5a39a0fbca898c55f637e311ec1ea44a10d9f3
4 files changed